Connecting link between glycolysis and TCA cycle is

Options

A. Link reaction
B. EMP pathway
C. ETC
D. Citric acid cycle

Answer

To solve the question "Connecting link between glycolysis and TCA cycle is," we need to understand the processes involved in cellular respiration, specifically focusing on glycolysis and the TCA cycle (also known as the Krebs cycle).

### Step-by-Step Solution:

1. **Understanding Glycolysis**:
- Glycolysis is the metabolic pathway that converts glucose into pyruvate. This process occurs in the cytoplasm and can take place under both aerobic and anaerobic conditions.
- The end product of glycolysis is pyruvate, which is crucial for further metabolic processes.

2. **Transition from Glycolysis to TCA Cycle**:
- After glycolysis, if oxygen is present (aerobic conditions), pyruvate needs to be converted into a form that can enter the TCA cycle.
- This conversion involves the decarboxylation of pyruvate, where a carbon dioxide molecule is removed, and the remaining two-carbon molecule is attached to coenzyme A to form acetyl-CoA.

3. **Role of Acetyl-CoA**:
- Acetyl-CoA is the molecule that enters the TCA cycle. This conversion from pyruvate to acetyl-CoA is a critical step that connects glycolysis to the TCA cycle.

4. **Identifying the Connecting Link**:
- The process of converting pyruvate to acetyl-CoA is known as the "link reaction" or "pyruvate decarboxylation."
- This reaction is catalyzed by the pyruvate dehydrogenase complex, which plays a vital role in linking glycolysis to the TCA cycle.

5. **Conclusion**:
- The connecting link between glycolysis and the TCA cycle is the "link reaction," which refers to the conversion of pyruvate into acetyl-CoA.

### Final Answer:
The correct answer is **link reaction**.